May 29, 2015: 1MDB gets a US$1 billion injection from Abu Dhabi's International Petroleum Investment Company, which will be used to repay a US$975 million loan to a syndicate of international bank lenders.

Jul 4, 2015: Najib rebuts allegations that he took money from 1MDB for personal gain.

Jul 7, 2015: A special task force formed to probe allegations that millions of dollars had been channelled into Najib's bank accounts announces a freeze order for six accounts linked to the case.

Jul 8, 2015: Malaysian police raid the 1MDB office.

Jul 9, 2015: The Malaysian Attorney-General's Chambers says that the six accounts which were ordered to be frozen were not linked to Najib, as his accounts with AmBank Islamic had already been closed by then.

Jul 28, 2015: Najib carries out a Cabinet reshuffle and axes then-Deputy Prime Minister Muhyiddin Yassin, days after Muhyiddin made his first public remarks on the 1MDB saga, asking Najib to explain the corruption scandal surrounding the state fund.

Aug 3, 2015: MACC says the special task force concludes the US$700 million that allegedly entered Najib's accounts were from donations, and not from 1MDB.

Aug 17, 2015: Thailand hands Swiss national Xavier Andre Justo a three-year jail sentence after he admitted to stealing information from his former employer, PetroSaudi International (PSI).

Nov 25, 2015: Former 1MDB CEO Shahrol Halmi is questioned by Malaysia's Public Accounts Committee (PAC) for four hours. He is later called back in on Nov 30 for further questioning.

Dec 1, 2015: PAC questions 1MDB president Arul Kanda Kandasamy.

Dec 5, 2015: Najib gives a statement to MACC on the issue of the almost US$700 million found in his personal bank accounts and on SRC international - a company originally owned by a state investment firm he advises.

Jan 14, 2016: 1MDB CEO Arul Kanda Kandasamy tells Channel NewsAsia that "there is no possibility" of him covering up the truth behind the company's debts.

Jan 20, 2016: Former 1MDB CEO Shahrol Halmi is once again called to testify in the ongoing probe of the state investment's funds operations.

Jan 26, 2016: Malaysia's Attorney-General Apandi Ali clears Najib of any wrongdoing, saying in a statement that US$681 million transferred into Najib's account was a "personal donation from the Saudi royal family". "A sum of US$620 million was returned by the Prime Minister to Saudi royal family because it was not utilised," the statement adds.

Jan 29, 2016: Swiss prosecutors request assistance from Malaysian authorities as they believe around US$4 billion was stolen from Malaysian state-owned companies. "A small portion" of the cash was transferred into Swiss accounts held by former Malaysian officials as well as current and former officials from the United Arab Emirates, the Swiss attorney general's office says in a statement.

Feb 1, 2016: Singapore's Commercial Affairs Department (CAD) and the Monetary Authority of Singapore (MAS) issue a joint statement, saying a "large number" of bank accounts in relation to a probe into 1MDB have been seized.

Feb 7, 2016: Saudi Arabia's Foreign Minister Adel Al-Jubeir says he believes the funds that went into Najib's personal account were not a political donation from the Saudi government, but that they had been part of a business deal.

Feb 19, 2016: 1MDB says in a statement that a Wall Street Journal report stating that it paid funds into the personal accounts of Najib is an "outright lie".

Apr 2, 2016: 1MDB denies reports that it provided funds to finance the movie The Wolf of Wall Street.

Apr 7, 2016: 1MDB's board of directors offer to resign after a report released by the parliamentary Public Accounts Committee said it found the state investment fund's financing and performance "unsatisfactory".

Apr 9, 2016: The Chairman of the Public Accounts Committee (PAC) Hasan Ariffin says there is no evidence to indicate any wrongdoing or abuse of power by Najib.

Apr 12, 2016: Swiss authorities expand its investigation into 1MDB to two former officials in charge of Abu Dhabi sovereign funds.

Singapore's Attorney-General's Chambers receives a request for legal assistance from Switzerland with regard to 1MDB.

Apr 13, 2016: 1MDB CEO Arul Kanda Kandasamy says the state investment fund could be a victim of fraud - after the Abu Dhabi sovereign fund, the International Petroleum Investment Company, denied receiving payment from 1MDB.

Apr 19, 2016: Mahathir applies for a court order to freeze Najib's assets.

1MDB says it is working to resolve the dispute with International Petroleum Investment Company.

May 24, 2016: The Monetary Authority of Singapore announces it has ordered the closure of Switzerland's BSI Bank in Singapore over "serious breaches of anti-money laundering requirements, poor management oversight of the bank’s operations, and gross misconduct by some of the bank’s staff".

May 31, 2016: Malaysia's Ministry of Finance announces the appointment of a new board of directors for 1MDB, succeeding the previous board.

Jul 11, 2016: 1MDB agrees to resolve its dispute with International Petroleum Investment Company via the London Court of International Arbitration.

Jul 21, 2016: United States Attorney General Loretta Lynch announces the filing of civil forfeiture complaints seeking the forfeiture and recovery of more than US$1 billion in assets associated with an alleged international conspiracy to launder funds misappropriated from 1MDB.

Aug 9, 2016: Xavier Andre Justo receives a royal pardon and has his three-year sentence commuted by one third.

Oct 11, 2016: The Monetary Authority of Singapore orders the Singapore branch of Falcon Bank to cease operations for serious failures in anti-money laundering controls and improper conduct by senior management. MAS also imposes fines on DBS and UBS banks for breaches of its anti-money laundering requirements. This comes after "supervisory examinations by MAS into 1MDB-related fund flows" that took place through the three banks from March 2013 to May 2015, MAS said.

May 30, 2017: The Monetary Authority of Singapore announces the completion of its two-year review of the banks involved in 1MDB-related transactions known-to-date. It says it has imposed financial penalties on Credit Suisse and United Overseas Bank, issued Prohibition Orders against three individuals and served notice of its intention to impose and same regulatory action on three others.

Jun 15, 2017: US authorities move to seize another US$540 million in assets, allegedly stolen via 1MDB and used to fund extravagant spending.

Jun 16, 2017: Filings by the US Justice Department in a civil lawsuit claim that nearly US$30 million of funds stolen from 1MDB was used to buy jewellery for the wife of "Malaysian Official 1".

Aug 1, 2017: International Petroleum Investment Company gives 1MDB five days to make a US$600 million payment, which it failed to pay on Jul 31. 1MDB says it will make the payment within the month.

Aug 2, 2017: Najib says 1MDB's failure to make the US$600 million payment to International Petroleum Investment Company was "a technical matter, and not a question of not being able to pay back".

Aug 11, 2017: 1MDB says it has remitted US$350 million to International Petroleum Investment Company. This comes after Abu Dhabi extended the deadline for 1MDB to make its US$600 million debt repayment, provided at least US$310 million was paid by Aug 12.

Aug 30, 2017: 1MDB says it has remitted the second tranche due on Aug 31, 2017, in full.

Oct 23, 2017: Malaysia asks Interpol to try to locate Jho Low for questioning over his suspected involvement in the 1MDB scandal.

Nov 1, 2017: The Monetary Authority of Singapore issues prohibition orders against two individuals involved in breaches related to 1MDB.

Dec 19, 2017: The Monetary Authority of Singapore issues more financial bans in its 1MDB investigation.

Dec 27, 2017: International Petroleum Investment Company says 1MDB has paid the settlement amount in full.

Apr 17, 2018: The Indonesian court orders the release of the 1MDB-linked luxury yacht, citing missteps by police in seizing the vessel.

May 10, 2018: Malaysia's Pakatan Harapan coalition - led by Mahathir Mohamad - crosses the minimum threshold of 112 seats needed to form Malaysia's new government, in a result that made political history.

May 11, 2018: Malaysia Prime Minister Mahathir Mohamad says his government will focus on the country's finances and economic management, and pledges to return billions of dollars lost in the 1MDB scandal.

May 16, 2018: Prime Minister Mahathir Mohamad says Malaysia is committed to paying any debt linked to 1MDB if it had been guaranteed by the government.

May 17, 2018: Malaysia's Council of Eminent Persons announces that a committee has been set up to look into matters concerning 1MDB.

Jun 19, 2018: Speaking to Channel NewsAsia, Finance Minister Lim Guan Eng says many claims by the United States Department of Justice are true. Lim says he does not expect to recover all the monies that have been lost.

Jun 25, 2018: Najib's former special officer is arrested by MACC to assist in its investigation into a case related to 1MDB. Channel NewsAsia understands that the man arrested is 42-year-old Amhari Efendi Nazaruddin.

Jun 27, 2018: Up to RM1.1 billion (US$270 million) of cash and luxury items were seized from premises linked to Najib, say Malaysian police. "This is the biggest seizure in the history of Malaysia," says Chief of the Commercial Crime Investigation Department Amar Singh.

Jun 29, 2018: The 1MDB taskforce says it has frozen several bank accounts of UMNO and other political parties believed to be involved in the misappropriation of 1MDB funds.

Jul 2, 2018: More than 400 bank accounts involving RM1.1 billion of funds from individuals, political parties and non-governmental organisations have been frozen, the 1MDB taskforce says in a press statement.

Jul 2, 2018: UMNO president Ahmad Zahid Hamidi spends nine hours at the MACC, where he gave a statement on the 1MDB case.

Jul 3, 2018: Najib is arrested in relation to the probe into SRC International. The Malaysian Bar says the 1MDB task force has no legal standing to arrest Najib.

Jul 4, 2018: Najib is charged in court with three counts of criminal breach of trust and one count of using his position for gratification.